1. Field of the Invention
This invention relates generally to a jacking apparatus for advancing a heavy load along an I-beam. As commonly arranged, a heavy load rests on two parallel I-beams and a pair of jacking devices, one on each I-beam, is arranged to advance the load, either by sliding it or rolling it on the I-beam. More particularly, this invention relates to a releasable clamping assembly which is responsive to a thrust load to mechanically urge a ramp plate, with a gripping surface, and a pair of opposed ramp mating members, each of which have gripping surface towards each other and into contact with the flanges of an I-beam which holds the releasable clamping member in a gripping relationship against the I-beam flange during application of the thrust force.
2. Description of the Prior Art
It is known in the art to utilize hydraulic apparatus including a jacking assembly to move a heavy load along an I-beam or other flanged member.
Specific prior art is disclosed in U.S. Pat. Nos. 3,373,971; Re. 26,905; 3,464,095; 3,559,954; and 4,007,915. Generally, the hydraulic apparatus shown in the art comprise a double acting hydraulic jack working in cooperation with a slot and latch assembly or a hydraulic clamping assembly. The latch and slot assembly or hydraulic clamping assembly mechanically grip the flange of an I-beam. Engagement of a latch in a slot formed in the I-beam or the hydraulic clamping assembly against the I-beam flange provides a temporary load path into the rail or support against which the heavy load from the jacking cylinder can react when applying force to the heavy load. The latch assembly or hydraulic clamping assembly is successively unlocked and repositioned and/or advanced to a new working location after each power stroke of the jacking cylinder. Typical applications of such jacking devices is for moving oil derricks on offshore platforms and for moving ships or ship sections in shipyards during construction or repair. Weights to be moved range from hundred of tons to many thousands of tons and the jacking forces needed, range from hundreds of tons to thousands of tons.
The known hydraulic clamping assemblies and latching asesmblies for accomplishing the above are described in the above referenced United States Patents.
Specifically, the hydraulic gripper for the derrick jack disclosed in U.S. Pat. Nos. 3,373,971 and Re. 26,905, wherein the inventor of the present invention was named in both U.S. Patents as one of the co-inventors, utilizes a hydraulic motor for developing the clamping force which moves or rotates side plates to drive jaws into gripping engagement with the bottom of an I-beam flange and which urges the top surface thereof against trunnion pins. The hydraulic clamping assembly reacts with the thrust force produced by a jacking apparatus to move a heavy load along the I-beam.
The hydraulic gripper and moving jack disclosed in U.S. Pat. No. 3,559,954, wherein the inventor of the present invention was named as one of the co-inventors, utilizes a hydraulic cylinder to generate the clamping force and a pair of rotatable jaw-like plates and shoes to grip the top and bottom of the I-beam to hold the hydraulic clamping assembly in fixed position against the I-beam to react with the thrust force produced by the jacking apparatus to move a heavy load along the I-beam.
U.S. Pat. No. 3,464,095 wherein the inventor of the present invention was the named inventor, discloses a hydraulic clamping mechanism utilizing a flattened tube lying inside of a "C" shaped chamber of a channel shaped gripper member wherein fluid is pumped under pressure into the tube pressing the channel shaped gripper member into gripping engagement with the I-beam to hold the same in fixed position during application of a thrust force thereagainst.
U.S. Pat. No. 4,007,915, wherein the inventor of the present invention was the named inventor, discloses a latching mechanism which cooperates with preformed slots in the flange of the I-beam to hold the hydraulic assembly in fixed position during application of a thrust force thereagainst.
U.S. Pat. No. 2,621,892 discloses a railroad car moving jack having a hydraulic actuated cylinder which operates a claxping assembly having a fixed clamp member and a moveable clamp member which forms a vise-like clamping assembly to grip the sides of a flanged member of a railroad track in response to a clamping force applied therebetween by the hydraulic cylinder.
The use of a vertical rotary holding table fixture, which rotates a bowl having an inwardly sloping center which receives and supports casing slips to grasp, hold and rotate well casings is likewise known in the art. Such devices are sold by Varco Corporation and are known as VARCO CMS-XL casing slips or VARCO SDML rotary slips.